Congratulations!

Ethiopian Airlines is probably your best bet to ADD. They actually release fairly decent award availability, and they have a decent product.

The unfortunate thing for you is that they are a member of Star Alliance - which means that they cannot be redeemed with Delta (Skyteam) or US (Oneworld as of today) miles.

You may, however, be able to use your Membership Rewards points through one of their partners - Aeroplan and Singapore Airlines come to mind. I would suggest reading up a bit in the Membership Rewards forum to determine if using your MR points is perhaps your best bet. If you think it might be a good option - then look to the specific forum for the respective transfer partner you intend to use for the ins and outs of each program.

Be sure to compare fuel surcharges on each program you consider, as I am fairly certain Aeroplan and Singapore add fuel surcharges (though I have absolutely no idea how high or low they might be on ET).

I don't know a lot about the specific programs you would likely be using, but I'd be happy to help in any way that I can. I know the process you're going through is likely very stressful. Don't be afraid to ask more questions here or send PMs to myself or others. The programs can get confusing - but don't get overwhelmed. You can definitely make it work.

Good luck, and welcome to Flyertalk.